A form of IVF that does not require women to take powerful drugs has a success rate similar to conventional IVF, according to data from the only UK fertility clinic licensed to carry out the treatment.

The team at the Oxford Fertility Unit followed 40 women who received the treatment known as in vitro maturation – including those who had the first babies born in Britain using the technique in October last year. Nine of the women became pregnant – a pregnancy rate of 33% in under 35s.

The data suggest that in vitro maturation (IVM) is a valid alternative to standard IVF – particularly for the 40% of women, including Victoria Beckham and Jamie Oliver's wife Jools, who suffer from a condition called polycystic ovary syndrome (Pcos). In conventional IVF, these women are vulnerable to ovarian hyperstimulation syndrome which can lead to a build up of fluid in the lungs and abdomen, and can in rare cases be fatal. The syndrome occurs in around 1% of standard IVF cycles, but around one in 10 cycles in women with Pcos.

In IVM immature eggs are extracted without administering drugs and matured in the lab for 48 hours. The researchers then fertilise the eggs by injecting sperm into them before implanting the embryos into the uterus. Because fewer drugs are necessary the cost of an IVM treatment cycle is substantially lower than standard IVF – £1,700 versus around £4,300.

Dr Tim Child at the Oxford Fertility Unit presented results from the 40 patients treated between February 2007 and March 2008 to the American Society of Reproductive Medicine's annual meeting in San Francisco. All the patients had polycystic ovaries.

Nine of the women achieved an established pregnancy (in which a foetal heart beat was recorded by ultrasound). All the patients were under 35, giving a pregnancy rate of 33% for that group and 23% overall. "Unstimulated IVM treatment is a viable alternative to standard IVF for women under 35 years of age who have ovaries of polycystic morphology," the authors wrote. "IVM avoids the potentially fatal complication of ovarian hyperstimulation syndrome in this at risk patient group."

The success rate of IVM compares favourably with IVF. According to the most recent figures (2006), the average success rate for IVF in under 35s was 29% across the country, although it was much higher in some clinics.

Dr Geeta Nargund, chief executive of the Health Education Research Trust and consultant in reproductive medicine at St George's Hospital in south London, said IVM would not work in older women. Their ovaries have fewer eggs, and because many eggs fail to mature in the laboratory, a high number are needed to begin with.